The present invention relates to a toner dispenser in a xerographic reproduction machine developer station and, more particularly, to a rotating dispenser which incorporates a fixed internal helical-type spring to improve the toner dispensing.
In prior art xerographic reproduction machines, the toner material used to develop a latent image formed on a photoreceptor surface is consumed in a development process and must be periodically replaced within the development system in order to sustain continuous operation of the machine. One technique which has become generally accepted is the use of a separate toner or developer hopper incorporating a toner cartridge for dispensing the toner into a hopper on a continuous, or on an on-demand basis. In addition, it has become common practice to use a toner cartridge, which, when placed in the machine, can be automatically opened to dispense toner. In such systems, a difficulty may arise in uniformly dispensing the toner from the cartridge, since the toner particles may tend to agglomerate, become compacted, and form a bridging structure in the toner container.
Various techniques have been developed to enable a reliable dispensing of toner from toner cartridges. U.S. Pat. Nos. 4,951,094 and 4,969,011 disclose toner developing systems in which toner cartridges are periodically rotated so that toner is dispensed through a series of ports extending along the length of the cartridge. U.S. Pat. Nos. 4,739,907; 4,943,830; and 3,724,725 disclose dispensing systems wherein the toner cartridge is stationary and an internal coil member is rotated to order the toner to a dispensing end, the rotating member additionally serving an anti-bridging function. U.S. Pat. No. 4,965,639 discloses a rotating cartridge which is slightly inclined to the horizontal so that toner is gravity-fed to dispensing ports located at one end. This system, however, lacks a toner transport and an anti-bridging mechanism.
The present invention is directed towards a dispensing system which dispenses toner on demand. The dispensing system includes a toner cartridge, which is periodically rotated to dispense toner through an exit port at a dispensing end. The toner in the cartridge is transported towards a dispensing end, while simultaneously being mixed and fluffed to assist such transport, by the action of an internal, coiled spring, which is held in place along the interior surface of the cartridge. As the cartridge rotates, the spring acts to both auger the toner towards the dispensing end and to keep the toner in a fluid-like condition to assist the toner movement towards the dispensing end. More particularly, the present invention relates to a xerographic reproduction machine which includes:
a movable recording member on which latent electrostatic images are created,
developing means for developing said images with toner, and
transfer means for transferring the developed images to a copy substrate material,
said developing means including a developer housing adjacent said recording member with means in said housing to bring developer from a sump in said housing into developing relation with said recording member to develop images on said recording member, said developing means characterized by including a toner dispensing apparatus for periodically dispensing toner into said sump comprising in combination:
a cylindrical toner cartridge positioned above said sump and containing a supply of toner therein, said cartridge having a plurality of toner discharge ports at one end thereof,
drive means for periodically rotating said cartridge, and
a relatively stiff, coiled spring member fixedly attached along the interior surface of the cartridge and extending along the length of the cartridge, said spring element adapted to transport the toner within the cartridge towards the dispensing end during rotation of the cartridge while simultaneously mixing the toner and making the consistency of the toner more fluid-like.